There is known a display device in which light emitting diodes (hereinafter referred to as “LEDs”) are arranged in a matrix pattern to thereby display an image (hereinafter referred to as an “LED display device”). In this LED display device, there is a problem in that, in a case where luminance and chromaticity of the LEDs being pixels are non-uniform, those are visually recognized adversely as luminance unevenness and color unevenness of an image.
As the causes of the luminance unevenness and color unevenness, there are given luminance dispersion and color dispersion generated due to dispersion in manufacture of the LEDs themselves, and temperature unevenness inside a substrate in which the LEDs are mounted in a matrix pattern (hereinafter referred to as an “LED mounting substrate”). In view of the above, a technology is proposed to suppress the luminance unevenness and color unevenness for each of the causes of the luminance unevenness and color unevenness.
As a technology for correcting the luminance dispersion and color dispersion generated due to the dispersion of manufacture of the LEDs themselves to thereby make the luminance and chromaticity uniform, a technology of Patent Document 1 is proposed, for example. In this technology, an image is taken with a camera, and a correction coefficient of each pixel for making luminance uniform is calculated based on luminance characteristics obtained from the results of the image taking, and the luminance is corrected using the correction coefficient, thereby being capable of making luminance uniform.
As a technology for suppressing the luminance unevenness and color unevenness generated due to the temperature unevenness inside the LED mounting substrate, a technology of Patent Document 2 is proposed, for example. In this technology, a cooling fan for cooling the LED mounting substrate is controlled based on luminance information obtained through image taking with a camera, thereby being capable of controlling suppression of the temperature unevenness, and further, the luminance unevenness and the like.